You are aware that scale effects are minimised by using models that do not differ in size from the prototype more than necessary aka physical similarity and dimensional analysis.
By very careful measurement (e.g. laser) for downscaling, the inherent problems of discrepancy of Reynolds number (whereby laminar flow exists in the model system although the flow in the prototype is turbulent) also relative departures of Froude, Weber or Mach numbers- can be avoided.
Calculations of inertia and pressure forces will also be simplified and porting your uber-accurate dimension maps to CFD and FEA saves a huge amount of time, effort and money.

The structural integrity of the Su-33 will not be difficult to calculate once the spar structure & layout are emulated for a static tester and composition of various alloys already known (titanium & high-strength aluminium alloys) they probably stripped down an Su-27SK for comparative analysis.
I’m sure FBW software wouldn’t pose that much of a problem for the 611 institute after the J-10.

I guess the greatest financial burden would be the capital expenditure for machine tooling and the greatest technical challenge- the engine……as you very well know :D.

Hey kiddo,

have you got any idea what you are talking about.

There are airplanes that is flying in the sky in this moment that I have had a hand in its design. can you say the same?

so I think you are way out of your league on this one.

Indian acquisitions always seem to have those caveats.

Wasn’t the internal bomb bay replaced with a fuel tank on some of the export models?

😀

…

oh no, its not as simple as patch it over with a skin and done.

The bomb rack was mounted onto a frame, so the frame was designed built to take that load, over built if no need to mount a bomb.

Not a bad idea,

The originally A-5 had alot of constraints.

1) wings is a strech of mig-19.
but most of time this thing would be in subsonic, so there is no need for the sweep. not efficient. for a CAS. I think for a regular Q-5 you would barely make over to mach one in low altitudes, and prob never with a decent load.

2) oh that internal bomb bay. alot of weight penalties. not needed.

Helos are notoriously maintainence night mare.

may not be a bad idea to rivive a rugged simple fixed wing aircraft which takes over your cas duties.

so, yeah, it is a good idea.

My reply in bold.

@Twinblade,

you reply shows a glimmer of hope, however dim, that your brain may carry a candlelight of understanding in this sea of nationalist cheap moral judgements. so I will reply.

>Test prototypes are mostly over engineered. Wouldn’t hurt to copy it.

Test Prototypes are mostly over engineered, so it actually would hurt to copy it, because the designer final intention are not known, unless Sukhoi gives you all the documentation on how and why somethings are done, for example, you wouldn’t be able to tell a beefed up structure as temp measure from a regular structure design from which it is meant to server a purpose. for example, its pretty typical on any airplane programs that the 1st couple of flight test articles are designed to be overweight, to be aerodynamic test platform so you basic aerodynamics and stabilty and controls are validated. only later series examples you go lower your structural margins.

Agreed. Needs a reasonable amount of computer modelling and verification via flying prototypes. A lot of these modifications can be made to safer J-11B prototypes from the learnings of T-10K purchased from Ukraine (barring the fbw code)

in absence of a data, basically the entire slew of database needs to build up, that means tens of thousands of hours of windtunnel and CFD… if you want this thing to go into serial production. flying prototypes is bit more risky because 1) flighttest data reduction wouldn’t give you enough and 2) when do you know your airplane would not fall apart?

Which frankly it isn’t. Despite the efforts needed for RE they are considerably less than designing, say a navalised J-10.

how do you know? were you involved in the navalized J-10? how do you know?

In any program there are essentially three risks: Schedule, Cost and Performance. ultimately for military everything falls back to schedule: certain things will be hit schedule at a certain date.

PLAN wasn’t in the position to backoff on the Performance risks, so Performance risks are tied intimately with Schedule risk. what J-15 offered was not necessarily less workload over J-10 Naval, it was a lower schedule risk approach ultimately.

by the time J-15 was decided J-20 was already awarded. so schedule risk carries the other dimension of the work load on an already fully engaged team. J-20 is a tier-1 program, without its success (schedule/performance) nothing else really mattered.

Other than components with very exotic materials technology and/or embedded software codes, most of the other components have to go through lesser amount of computer simulation during the design phase. Besides it is easier to plan the production assembly in advance when you RE a design.

why lesser? If I only have an example of a aluminum wing spar but do not know anything about the material properties, the loads distribution down to component, the stress concentrations, etc. can you build this thing and put it together? I am not even a loads and stress guy and I can tell you hell no.

So instead of going through 10-15 design iterations and verification, all the RE guys have to do is go through at max 2-3 designs in the ball park of the original (sometimes even a direct copy) and they can manage to achieve the same ball park performance. The original designer puts in hundreds of thousands of man hours while the RE guys manage to pull it off in a fraction of man hours while building their work on the efforts of the original designer. You know why it is called IP theft ? Because it is what it is, plain 2 bit thievery.

first of all, lay off on the moral judgement, because 1) you don’t have the knowledge to make the judgement and 2) its sounds really out of the place in this line of discussion.

second. If you ever seen a real labor burn down chart….its typically in the regions of “million” man-hours.
typically on a new program, the first 13 of the “10-15” design iterations are done mostly on paper with a prelim-design group at most. most of these are just basic trade studies (sometimes done on sometimes excel spreadsheets 🙂 I kid you not) the rounds of windtunnel test to firm up the basic performance characteristics of your final candidate design sketchs, compare to actual execution phase, is laughablly small.

The final 1 may be 2 rounds, is where you see the company spend most of the “million+” man hours.

Wait…. what ? *sarcasm on* I think Chinese should offer an upgrade to Su-33 fleet *sarcasm off*

Instead of a cheap shot, I will say this: they prob could.
given that they have put this thing through the gauntlet of tests with different tools than Sukhoi and at a fresh angle. There is no where anywhere written in stone that student can not be better than the teacher, and RE can not be better than the original, if it were, then human civilization is doomed to failure.

Sukhoi isn’t one of them. They sell you a product and help you produce it. The lessons from the license production are for you to absorb, for it is what you have paid for. Taking a design from someone who isn’t willing to sell at whatever price being offered is like kidnapping someone’s child when they don’t want to sell it to you. Even if you take great pains to teach him to scrub, do the dishes, clean the chimney, it won’t change the fact that its not yours.

again, layoff your moral heapings, last thing we need is for someone to take the church pulpit and moralizing.

In the originally co-production agreement for Su-27SK. they actually did hand over rather large amounts of technical data… not only for production purposes but aerodynamics, L&D, etc. etc. not all, but alot. so they would actually go for it.

the original point is co-production doesn’t grantee that it will get you anywhere. but RE will! look at how Tu-4 influenced Tupolev. look at how V-2 influenced russian rocketry.

It isn’t the key but its a vital component in reducing the “generation gap”. The Mki deal enabled us to grow over the production facilities barely sufficient to manufacture Jaguars and MiG-21’s, the stagnation due to near economic collapse not withstanding.
The MMRCA circus is in effect a guarantee the infusion of latest manufacturing technology, which coupled with increased investments in HAL and various DRDO labs will enable us to become self sufficient to design as well as manufacturing.

I am not saying those things are not necessary. These things are prob verygood and necessary.

What I am saying is these things that you mentioned are not sufficient.
Various Labs would never enable you any “Design” sufficiency, because by definition DRDOs labs are disconnected parts and no where close how an actually airplane company is organized. Essentially you need an actual airplane program that goes through conception to end, to hit all the major stages, to train a core of engineers and managers in an organization, so sufficient number of them can actually breed a “ah-ha” moment, and give birth to something else.

But its way easier than starting from scratch

Especially while RE, because it takes lesser man hours

Agree. If it shoots, it can kill too, copy or original

Especially when it concerns IP infringement and reverse engineering

*Not necessarily, as I have just show you.
(and if you really don’t believe that, I can give you bunch of time history traces and ask you back out the coefficents of the equations. see how easy of a time you would have.)

*Not true, as I have just informed you.

*Especially when it concerns IP infringement and reverse engineering

*other than asking you if you are done with your morality plays, I would just ask how are you so sure that they are not paying royalties to Suhkoi??

If you look from “technical” point of view, yes reverse engineering takes a lot of effort. In fact under certain cases one can waste more time and money trying to figure out/troubleshoot something and a better approach could be of redesigning the thing. But buying a license costs money which comes from great effort as well, especially if you are a developing country and your country is not living off its natural resources. Here you are paying extra i.e. profit the seller is making on top of it.

When Have I ever deviated from the “technical” point of view?
😎
to me effort means one thing which is labor and hard work that goes into an engineering product.

also on a tangent note, it’s not like china didn’t try to buy the design.
russians prob won’t sell the technical data along with it. that’s what blew the deal off.

==== warning, sensitive nationalist please turn back before getting their feelings hurt ========

if you can;’t handled the truth then you shouldn’t be here reading rest of this post 🙂

==== warning, sensitive nationalist please turn back before getting their feelings hurt ========

btw, looks like most of you guys have no idea how to build an airplane.

so chinese by getting an Su-33/T10K example what do you actually get?

1. an outer mold line, one that is suspect to tolerance at that.
2. some structure design details.
3. some performance details they can backout from limited flight test.

that is it.

u can’t make a good copy just by having those.

because, you don’t have and these things are critical:
1) aerodynamic database.
2) structure dynamics/loads database.
3) stress analysis that shows your tolerance and structure design is valid.
4) flight control software.
…

all of what i mentioned above is what you need for a real production aircraft and just having a physical example don’t get you that. may be you can get away with with a sopwith camel but no, not a supersonic stobar fighter.

so what’s required:
1) redoing windtunnel and Cfd, all of them, so you can back out a aerodynamics database,
2) structure dynamics design so your loads and stress number for your major components down to individual parts would be correct. so you can actually now make these parts.
3) redesign of flight control software based on above two.
4) system level hardware.
….
the amount of work sounds like new airplane?…

(of course, what I said above would prob not resonate with glossy airplane porn consuming nationalist amatures… nor witheven most aviation journalist for that matter. )

so somehow you think you can have replicator and clone an airplane from an example…:rolleyes:
again, I would have to say, most of you guys have no idea, technically, the effort it takes to pull a RE off… so lead you guys to think it is “easier” route.

But on the flip-side, you get to learn much more by going through all of that, you will learn how good your analytical and experimental techniques are… fixing prob and coming up solutions that the sukhoi bureau themselves prob never knew, areas you can improve, insight on how vehical dynamics work together synergitically on a real airplane etc etc.

These things you will never learn if you have gone with Co-production and consultants, doesn’t matter how much $$$ you pay. these things would be considered the core-capability, their inhouse experties, the real IP, of the airplane makers. sounds familiar? because it is. FGFA sounds very nice but HAL has to push/pay lots of $$$ to get a 25% workshare and most of them are in systems, just so they can essentially get a chance to do a T-50UBK, and put a 2nd seat onto a platform.

couple of posts ago I hinted at the reason why Chinese and Indian aerospace industry are different. Quadbike mentioned is a function of money, I alluded to that fact that chinese even got less money when they learned most of these stuff, and differed in his opinion.

the schpill I gave above is really how chinese built up some of their core capability and why India seems to lag behind, somewhat.. .if it keeps on going doing ToT and co-production with russians/brits/Americans thinking that would be the key. (indian nationalist, please hold your fire :cool:)
Luckily, the difference is that (not that chinese has more money, smarter, or don’t care about IPs),
Chinese didn’t have a choice, it went under embargo most of the past 60 years and still is. and Russians wouldn’t sell anything because they would put russians out of business.

back ’59 they had to finish setup production line for Mig-21F-13 by themselve with incomplete soviet data and no help and also produce variants. that whole difficult experience trained their aerodynamicists and engineers. the chief designer of J10A wasn’t even a that good of aerodynamicist until he was put in charge of RE mig-21MF at a secondary factory in Chengdu.

why am I being so nice…damn, I am giving away the secrets of the chinese aerospace industries.

—–
p.s.

so what have we learned today:

1) It;s harder to RE but you get more out of it than you typically would think.
2) money is not the key to success.
3) lay off on the moral superiority stuff.
4) nationalism blind you.
5) lots of chinese aviation history.

——-
p.p.s.
sorry if I have offended anyone’s sensibilities with the post. but if you can;’t handled the truth then you shouldn’t be here reading my posts 🙂

why hang yourself on a single tree?

why go for a single engine source?

Go for 2x medium.

multiple options and export friendly.

Am not saying its simple just saying its illegal.

My contention is not with the question of legality,

but with someone implying being seen “illegal”, or prim-and-proper, somehow equals less effort.
if anything the real world is other way around.

in blue.

Something wrong in using consultants when you own the IP rights to the existing design and it follow up ?

I am not a IP lawyer so I don’t pretend to know anything about IPs.

It’s mainly the part of “own efforts” I find bit funny,

I really don’t get what you are trying to convey. ToT’s fit perfectly within the scope of idealism and pragmatism.

Own efforts =/= IP Rights.
IP Rights =/= Own Efforts.

Sometimes “Copying” takes more effort than “acquiring IP rights”,

If the Ideailism means going the hardway it doesn’t mean do everything prim-and-proper